Process of dyeing acetyl-cellulose.



Ho Drawing.

Ill-MIL KNOEYENAGEL, F HEIDELBERG, GERMANY.

' PROCESS OF DYEING ACETYL-CELLULOSE.

Specification of'Letters' Patent.

Patented. Dec. 27, 1910.

Application filed January 17, 1910. Serial Ito/538,474.

,To all whom it may coa cem:

Be it known 'that'I, 'EMii. KNOEVENAGEL,

I professor of chemistry, a subject of the German Emperor, residing at Heidelberg, in the Vented certain new and useful Improvements Srrand Duchy of Baden, Germany, have. in-

' in'Processes-of Dyeing Acetyl-Cellulose, of

which the following is a' specification.

Acetyl-cellulose, being more or less waterrepellent, cannot-be dyed at all or only very feebly by the'ordinary processes of dyeing in aqueous solution. I have discovered, howi ever, that acetyl-cellulose and products such as filaments made from the same are capable of absorbing a great variety of-phenols and derivatives of these compounds, and that acetyl cellulose abstracts these substances even from dilute aqueous solutions. In this 'mannerit is possible, to" produce in acetylcellulose,'i'n the presence'of water, solutions of phenols, even of those, which are very sparingly soluble in water, and to utilize these solid solutions for the production of coloring matter on the fiber or'filament in the known manner; For instance, the solid solutions of phenols in acetyl-cellulose may be utilized for producing colorlngmatters on the fiber by coupling with aqueous solutions of diazonium-salts. I I

In the process of dissolving phenols in --acetyl-cellulose I may transform or decom pose salts of the phenols by means of the equivalent quantity of'bases or acids, or I may promote the liberation of the "phenols by the presence of suitable bases or acids in such a manner that said phenols are simultaneously absorbed by the acetyl-cellulose.

In some ca ses the absorption of the phenols by acetyl-cellulose takes place directly from the solutionsof their s1 lts, but as a rule the I absorption is facilitated by previously liberatingthe phenol from its salts, as mentioned above.

Salts'of coloring matters are frequently in the presence of ammonia, in case we are dealing with saltsof bases, and in the presence of acetic acid, etc., if salts of acids are dealt with, than would be the case with the salts alone. i v

The following examples will serve to explain the process .51, Impregnqtz'on with beta naphth0Z.- Filaments of acetyl-cellulose were impregnated for half-an hour at the temperature of a Water bath in about a 0.5% solution of beta naphthol and briefly rinsed with water.

1 Filaments treated accordingfto I Were coupled in about a 1.5% of p-nitranilin hydrochlorid solution, which had been diazotized and mixed with sodium acetate. Nitranilin red was formedon the fiber.

1 In filaments treated according to 1 alpha-naphthylamin bordeaux was produced on the fiber by means of alpha-naphthylamin similarly to 1*;

2. I mpregnatz'on with p-ami'ho Meal- Acetyl-oellulose was impregnated with about a 0.5% aqueous solution of p-aminophenol at water bath temperature for about 10 minutes.

produced.

hat I claim is The improvement in the art of dyeing acetyl-cellulose, which consists in treating the aeetyl-cellulose with a phenol in aqueous solution. then rinsing it with water and then dyeing it in the dye-bath, substantially as described. In testimony my hand in presence of two subscribing witnesses. v

'. IiM L KNOEVENLGEL.

Witnesses:

WALTER WEBER, HnpMANN TAEGER.

whereof I have hereunto set 

